A common technique for installing sheet elongate members such as piles, anchor members, caissons, and mandrels is to use a vibratory machine, such as a pile driver or vibratory hammer, supported by a support apparatus, such as a crane or the like. In the instance of a pile driver, one end of the vibratory pile driver is supported by the crane, such as via the hook connected to a sling, and the other end of the vibratory pile driver drives against the piling to thereby drive the pile into a ground surface.
Generally, the vibratory pile driver can include a set of eccentric weights, such as cams, which are rotated at high speed to cause the vibratory pile driver to vibrate. The vibratory force created by the vibratory pile driver is then transferred against the end of the pile to thereby drive the pile into the ground surface.
During start-up and shutdown phases of such vibrating equipment, there is generally a considerable amount of vibratory force that transferred to the support apparatus, such as the crane, via the sling. In particular situations, the vibratory force transferred to the crane can lead to a, number of failures. This can include boom failure, excessive wear and tear to major structural components such as pins, sheaves, track gear, and acceleration of structural and metal weld fatigue. These failures can therefore drastically reduce the lifetime of the machines.
Whilst a number of dampening devices have been proposed in the past, these devices generally use elastomeric material to absorb a portion of the vibratory force. However, due to shear strain that is applied to the elastomeric material, these components of these device wear. Furthermore, depending upon the vibratory force that is being transferred, dampening properties of the elastomeric material cannot be altered according to operating conditions.
Therefore, there is a need for a vibration dampening device that overcomes or at least alleviates one or more of the above-mentioned problems, or at least provides a useful commercial alternative.
The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.